Utilities: Letting your service professional know about moving utilities helps him better judge how much work will be necessary to complete your project. For instance, bringing in plumbing, electricity or a gas or phone line might necessitate structural or wall changes. It will also let him know if he needs to contact other tradespeople to finish the project.

Adding a ceiling fan to a room can help heat and cool it in a charming way. Remember that blade tips must be at least two feet from walls or sloped ceilings and that they should never be mounted lower than seven feet from the floor.

Outlets and switches: In recent years there has been something of a design renaissance in light switches, with new switches offering a wide array of features, like full-range dimming, a delayed fade from on to off, dimmers that remember a range of different settings, switches that automatically turn on lights when a person enters the room, central lighting controls that operate lights anywhere in the house, even hand-held infrared remotes. Make sure you have enough outlets and switches to run every electrical appliance you have. It's not a bad idea to add a couple extra of each for future appliance additions.

Rental unit: If you're creating a rental unit, you might want to add a new electrical service for the addition to separate your usage from your renter's. Or you might want to add a new subpanel, a smaller panel that has its own set of circuit breakers leading to household circuits and may be located in a different part of the house than the main panel.

Heating options: Think about your heating options during your remodel or addition. You can simply tie the new room into your existing heating system or use any of a number of options.

If you choose radiant in-floor heating, which uses hot water to heat your floors, your service professional might need to hire a plumber; electric baseboard heat might require an electrician.

A forced-air heating system draws the room air through ductwork to a furnace, where the air is filtered and heated. Most manufacturers make several sizes of each model. These furnaces come in "upflow," "downflow" and "horizontal" models designed to accommodate basement, attic or limited-space installation. A forced-air system can be combined with an air-conditioning unit, a humidifier and an air filter.

Electricity is a relatively expensive heating fuel. In most areas, electric heat is best reserved for specialized applications, such as heating an added-on room, temporarily warming a bathroom, or heating a home where other more affordable fuels are not available.